For air conditioning
on a cruising boat there are two major considerations - first, how often are you going to use it. And secondly, what does it cost.
Cruising in the islands generally provides excellent constant winds and breezes that along with being surrounded by water
keeps the boat liveable. Most important is having a good coverage awning over the top of the boat. There is a dramatic decrease in the heat getting to the boat if you have a good awning. Some people even do "double awnings."
Of course if you are in a marina or land-locked/blocked bay or cove there may not be much in the way of winds and breezes. Marinas
are probably the places where having air conditioning becomes a priority. And if you are in a marina, you have electricity available to run just about anything.
As an aside, remember that the best form of "air conditioning" for an anchored cruising boat is to divest yourself of all apparel and do a "swan dive" into the water. Evaporation when you emerge will really cool things down.
In the second major consideration, cost - portable Walmart/Home Depot/Target/ etc. type window air conditioners are about as inexpensive as you can get. And a 5,000 Btu or 8,000 Btu unit is not that large.
If you have sufficient money
that air conditioning on the boat is "expected" then you can afford to have an "installed" unit and run it off the boat's genset.
But for "frugal" cruisers, you can't beat the window air conditioners. They are both small and extremely frugal on electricity. But you need some AC electricity to run them. The "suitcase" generators like the Honda EU2000i and others operate as DC generators with a built-in inverter
to produce the AC power needed for the air conditioner. The big difference between these type generators and all the others is weight and noise
. Classical AC generators are quite loud.
Mounting a window air conditioner on a boat's hatch is quite easy. You put the air conditioner's bottom lip over the hatch ring. Then use blocks to hold up the air conditioner so that it can drain water outside the boat rather than inside through the hatch. Then lower the hatch so it rests on top of the air conditioner.
Use R-Max foam insulation
board/panels and cut triangles and rectangles to fill the resultant open gaps between the hatch parts
and air conditioner. I use the aluminum
duct tape to hold everything in place and seal the opening so water and rain cannot get inside. That's all there is to it.
When it is time to move you use a razor knife to cut the aluminum
tape and remove the R-Max panels
. Then the air conditioner and panels
get stored in the #2 head shower
or lazarette or another space in the boat.
The idea is that the discount store window air conditioners are small, efficient and inexpensive. Fancier systems of installation
like through companionway
wash boards also works well. I have seen some folks who install plastic deck storage
hatches in the side of their cabin
top designed specifically for the window air conditioner.
But do all this before you leave North America - the window-style air conditioners are becoming extinct and just do not exist outside North America. What is available is the one piece push around portable air conditioners with the "dryer vent hose" for exhausting hot air overboard
. They are big, clumsy and a royal pain in the butt to try to adapt to a boat.